In a large bowl, mash the black beans with a fork or potato masher until they are mostly mashed but still have some texture for a chunky feel. You can leave some whole beans for extra bite.
Add the breadcrumbs, chopped onion, bell pepper, minced garlic, soy sauce (or tamari), cumin, smoked paprika, salt, pepper, ground flaxseeds (if using), cilantro, and lemon juice to the mashed beans. Mix everything together until well combined. If the mixture feels too wet, add a little more breadcrumbs to firm it up.
Shape the mixture into 4-6 equal-sized patties, depending on how thick you want your burgers. You can use your hands or a burger press to make them uniform.
Heat 1 tablespoon of olive oil in a large skillet over medium heat. Once hot, add the patties and cook for 4-5 minutes on each side, until golden brown and crispy on the outside. You can also bake them at 375°F (190°C) for 20-25 minutes, flipping halfway through.
Once the patties are cooked, place them on burger buns and top with your favorite toppings—lettuce, tomato, pickles, avocado, or a drizzle of vegan mayo or ketchup.
Serve immediately and enjoy your delicious, homemade black bean burger!
